1. Field
This invention relates to exercise machines, and more particularly to stepping machines which stimulate the climbing of stairs or steps.
2. State of the Art
Stepping machines provide a form of aerobic exercise by simulating stair climbing. In such machines, the user's body is repeatedly lifted by alternatively shifting the user's weight from one foot to the other, each foot resting on its own treadle. As the weight is shifted to a treadle, the weight overcomes a resistive force to move the treadle downward. In conventional stepping machines, the treadles are interconnected so that as one treadle is pushed downward under the user's weight, the other treadle is mechanically moved an equal distance in the opposite direction, i.e., upward. Repetitive weighting and unweighting of the user on each treadle in a sinusoidal type reciprocating motion results in the aerobic exertion.
An example of a conventional stepping machine is shown in U.S. Pat. No. 4,830,362 of Bull. A pair of foot pedals or levers is interconnected to move in opposite directions. In addition, the apparatus includes a pair of handles interconnected in synchrony with the pedals.
Conventional stepping machines have treadles which are mechanically interconneced so that the treadle positions are always 180 degrees out of phase. Thus, as the left treadle is at the uppermost position, the right treadle is at the lowermost position. Downward movement of one treadle moves the other treadle and the foot placed thereon upward. This upward motion does not simulate the natural lifting of a foot from one step to the next upper step. The natural climbing or stepping movement deviates from a strict sinusoidal curve, the lifting of the unweighted foot occurring at a speed different from the weighting motion.
In conventional stepping machines, the interconnected treadles may be stopped at any position. In the most comfortable position, one foot is usually fully weighted to drive the associated treadle to a lowermost position. The other treadle is then at an uppermost position. If desired, the treadles may be equally weighted and both be maintained in an intermediate position. Thus, there is no machine driven motivation for the user to maintain a particular stepping speed.